Various fuel injection devices have been designed to transmit pressurized fuel through an injection nozzle into a combustion chamber of an engine. Typically, an injection nozzle will have one or more orifices formed in an end thereof, and a selectively movable check member will be arranged inside the nozzle to selectively permit or prevent pressurized fuel from exiting the nozzle through the injection orifices. The geometric configuration of a nozzle-check assembly may significantly impact various injection device characteristics, such as (i) injection device longevity, (ii) injection device cost, (iii) fuel injection repeatability, and (iv) engine exhaust emission levels, for example.
U.S. Patent Application Publication No. US 2003/0057299 A1 discloses a fuel injection nozzle having a nozzle body with at least one injection port therein, and having a nozzle needle that is displaceable within the nozzle body. The nozzle needle has a radial shoulder and, downstream of the shoulder, a circumferential groove that extends to the injection port. The radial shoulder is embodied with very sharp edges, presumably to reduce the effect of production variations. The recited object of the invention disclosed in the '299 publication is to provide reliable fuel metering.
Prior fuel injection devices may be improved by providing novel configurations and methods that effectively balance injection device longevity and cost, injection repeatability, and engine exhaust emissions effects.
The present invention is directed to overcome or improve one or more disadvantages associated with prior devices and methods for controlling the injection of fluid.